CLASS-VIII

METALS AND NON-METALS

WORKSHEET-M1

Q1. Give reasons:

a)      Copper and iron are used for making cooking utensils and water boilers.

b)      Silver, the best conductor of electricity is not used for electrical wiring purposes.

Q2. Why metals lose their shine on exposure to air for sometime?

Q3. How will you show that copper is a good electrical conductor?

Q4. Magnesium ribbon is burnt in the presence of oxygen to form compound A. This compound

       A  is dissolved in water to form compound B.

a)       Write chemical formula of compound ‘A’ & compound ‘B’.

b)       Write the equations involved in the formation of compound ‘A’ and compound ‘B’.

c)       Name the indicator used to detect the nature of compound ‘B’.

d)       State clearly the change in colour of the indicator when it is dipped in compound B.

e)       What does this colour change confirm?

Q5. When iron reacts with hydrochloric acid, a gas is evolved.

a)       Name the gas evolved.

b)       Write the chemical equation for this reaction.

c)       How can you identify this gas?

Q6. a)    What is the criterion for arranging the metals in the reactivity series?

b)       Arrange the following metals according to the decreasing order of reactivity:

Fe, Mg, Pb, Cu.

      

c)       When the most reactive metal of the above reactivity series is exposed to air

Which compound is formed? Write its name.

d)       Write two uses of the last member of the above series.

Q8. Name the metal which is extracted from:

a)       bauxite ore

b)       haematite ore

Q9. Name the:

a)       most reactive metal

b)       least reactive metal

Q10. What happens when a copper wire is dipped in zinc sulphate solution?

      

CLASS-VIII

FORCE AND PRESSURE

WORKSHEET- FP1

Q1. When two forces applied on an object , are equal and opposite, then these forces

a)      may move the object

b)     may stop a moving object

c)      may move the object and also cause a change in its shape

d)     do not move the object but may cause a change in its shape

Q3. In a game of tug of war, the Team ‘A’ is pulling the rope with a Force F₁  and the Team ‘B’ is pulling it with a Force F₂ . Team ‘A’ won the game. The resultant force is:-

a)      zero

b)     F₂ – F₁  and the force is exerted in the direction of A.

c)      F₁ – F₂  and the force is exerted in the direction of B.

d)     F₁ – F₂  and the force is exerted in the direction of A.

Q4. The same force is applied for the same time to a car and a loaded truck. Which of the two will pick up greater speed and why?

Q5. Identify the kind of force present in the following situations:-

i)                    The moon revolving around the earth.

ii)                  A balloon filled with air and rubbed against wool getting attracted towards the wall.

Q6. A bull is pulling a cart.

i)                    Name the force of action used in this process.

ii)                  Name the two objects in the above case between which interaction is involved.

Q7. Which effect of force is associated with:

i)                    squeezing a tube of toothpaste?

ii)                  throwing a ball vertically upwards?